A. Prolonged heating:
B. Rapid heating me
C. Water film contamination
D. Too high pressure during casting
Related Mcqs:
- Casting flux is used to_______________?
A. Prevent the oxidation of the metal during melting
B. increase the melting point of the flux
C. Flaring the point of the sprue attachment
D. None of the above - Mental spines provide attachment to_____________?
A. Genioglossus
B. Anterior & Posterior bellies of digastric
C. Mylohyoid
D. Superior constrictor of pharynx - Schuffner’s dots are seen in infection due to_______________?
A. Plasmodium falciparum
B. Plasmodium vivax
C. Plasmodium malariae
D. Plasmodium ovale - Resistance to corrosion in a cobalt-chrome casting is due to presence of_______________?
A. High quality iron
B. Chrome
C. Cobalt
D. Nickel - Glossy smooth margins of a casting are due to_____________?
A. Shrinkage of alloy on cooling
B. Investment breakdown
C. Incomplete wax elimination
D. Incomplete gas elimination - Air bubbles formed on the surface of casting is probably due to________________?
A. Improper casting pressure
B. Improper heating of the investment
C. Improper angulation of sprue
D. Improper wetting of the wax pattern by the investment - Gap between true end of casting ring and wax pattern should be______________?
A. ¼ inch
B. ½ inch
C. 3/8 inch
D. one inch - Reduction in the fusion temperature of dental gold casting alloys is caused by presence of______________?
A. Platinum
B. Copper
C. Silver
D. Gold - Titanium casting is done_____________?
A. Under vacuum in argon atmosphere
B. Under air pressure in nitrogen atmosphere
C. In specially fabricated aluminium vanadium
D. Using CAD-CAM technique - Modern dental noble metal casting alloys generally have equiaxed fine grain structures because of the incorporation of small amounts of______________?
A. Chromium
B. Indium
C. Irridium
D. Palladium
